This Rugged Leather farming guide is made to help you farm Rugged Leather. I decided to search for places with a high density of mobs which I can skin and drop Rugged Leather. I traveled around Azeroth, and after a while, I made a list of places.
The recommended skinning skill for farming Rugged Leather is around 280. If you farm at these places with lower Skinning skill, you will get a lot of lower-tier Leather until you reach 280.
Rugged Leather
Before you go anywhere, clear your bags first. That’s because for skinning the animals, you need to loot them first. This means you will gather a lot of junk stuff filling your bags.
Onyxia's Lair - Dustwallow Marsh
The best place to get a lot of Rugged Leather is Onyxia's Lair at Dustwallow Marsh in Kalimdor. You will find the location to the entrance at the green swirly icon on your world map in Dustwallow Marsh. Onyxia's Lair is a level 30 raid instance, so only level 40+ players can farm here.
There are 4 Onyxian Warder inside Onyxia's Lair. They can drop up to 20 
Rugged Leather each, but they also drop 
Rugged Hide, so the number of leathers you get will vary a lot.
DON'T KILL ONYXIA! You can't reset the trash mobs if you kill the boss.
After you cleared the instance, run out, then you have to reset it by right-clicking over your own portrait, and then click the "Reset Instance" button. This restarts the whole instance, and all mobs will be back. You can only do 10 instance runs in an hour.
Sometimes you will get Rugged Hide from all 4 mobs, so the place will seem like a horrible place to farm, but if you add all 10 runs together, you will still have more Rugged Leather overall than any other farming place. (unless you actually have the worst luck on the planet and you get nothing but rugged hide).
If the mobs don't drop any leather when you skin them, then go to Shattrath and learn Outland skinning from Seymour. This is a known bug, and for some reason, learning Outland skinning seems to fix it for most people.
Blasted Lands
Blasted Lands is the best place to farm Rugged Leather if you can't farm at Onyxias Lair. You will skin Ashmane Boars, and other various beasts like Snickerfang Hyena, Felhounds etc.
NOTE: If you are level 50, half of this area will be phased, and there will be a bunch of different mobs there instead of the beasts. But, if you talk to Zidormi, she will allow you to switch between phased/low-level and high-level versions of the Blasted Lands. (if you open the map, she will be marked with a white text bubble at north)
Winterspring
Ice Thistle Yetis in Winterspring have about only a 60% chance to drop Rugged Leather when skinned, so you will also get a lot Thick Leather. This drop rate is lower than the drop rate in Blasted Lands, however, these mobs are a lot closer to each other and there is a lot of them, which makes this a great place to farm Rugged Leather. There is a cave at this spot, you should go and farm inside the cave
These are my favorite places for Rugged Leather farming. Contact me if you have other great farming spots!
Visit my Knothide Leather farming page when you have enough Rugged Leather!